Zinc-based metal-organic framework as well as preparation method and application thereof

Abstract

The invention provides a zinc-based metal-organic framework and a preparation method and application thereof, and the preparation method comprises the following steps: mixing a zinc source, a ligand, a catalyst and a solvent, carrying out a reaction, and after the reaction is finished, carrying out post-treatment to obtain the zinc-based metal-organic framework, wherein the catalyst comprises any one or a combination of at least two of soluble ammonium salt, soluble salt containing metal ions or acid. According to the preparation method provided by the invention, high-temperature and high-pressure equipment is not needed, the environmental condition is mild, the preparation process is simple in process, safe and controllable, the production difficulty, cost and equipment requirements are greatly reduced, and the reaction rate, the product yield and the space time yield are greatly improved under the assistance of the catalyst. The preparation method is green and environment-friendly, the zinc-based metal-organic framework with the adjustable structure and performance can be prepared, and the zinc-based metal-organic framework has very high industrial production prospects and is suitable for application and popularization.

Description

Technical Field

[0001] The present invention belongs to the field of novel functional materials, and particularly relates to a zinc-based metal-organic framework and its preparation method and application. Background Art

[0002] Metal-organic frameworks (MOFs) are porous crystalline materials with a certain topological structure formed by the connection of metal ions or metal clusters with organic ligands. Since the Yaghi research team first reported MOF-5 with a three-dimensional porous structure in 1999, MOFs materials have become a new type of material that has attracted much attention in recent years because they usually have high porosity, structural periodicity and tunability, and are easy to functionalize, have adjustable pore sizes and structural diversity. They can be widely used in the fields of adsorption, separation, catalysis, energy storage, sensors, drug delivery, and carbon sequestration.

[0003] An important branch of MOFs materials is zeolitic imidazolate frameworks (ZIFs). Currently, the most studied is a class of metal-organic framework compound materials formed by the coordination and self-assembly of Zn 2+ or Co 2+ with imidazole, which overcomes the disadvantages of poor thermal stability, water stability and chemical stability of MOFs materials to a certain extent. A typical representative is ZIF-8, which is a material with a zeolite-like framework topological structure obtained by the coordination of Zn 2+ and 2-methylimidazole, and has a high specific surface area and good thermal stability, water stability and chemical stability.

[0004] In the development process of the synthesis and application of ZIF-8, researchers have continuously explored new methods to synthesize products with good crystal structure, excellent performance and high specific surface area. However, with the increasing attention to environmental problems, in response to environmental problems related to the depletion of non-renewable resources, environmental pollution, global warming and biodiversity loss, people are striving to find new materials and environmentally friendly synthesis strategies as "green" processes. The synthesis method of ZIF-8 materials has gradually developed from the solvothermal synthesis and hydrothermal method of materials under high temperature and high pressure to room temperature and more energy-saving methods, such as room temperature co-precipitation method, sonochemical method, microwave method, mechanical method, etc.

[0005] Patent CN108290134A discloses a "ultra-fast high space-time yield synthesis of metal-organic frameworks", which is a general synthesis method for MOFs materials, partially overcoming the disadvantages of known methods. In particular, the synthesis of copper(II) benzene-1,3,5-tricarboxylate (HKUST-1) has very good yields (based on raw materials) and space-time yields, and it is a new method for preparing MOFs in the form of uniform powders. However, for the synthesis of zinc-based metal-organic frameworks, using basic zinc carbonate as the raw material, the atom utilization rate is not as good as that of ZnO and Zn(OH)2. In addition, its yield (based on raw materials) is only 88%, and there is still some room for improvement to reach 100% conversion, resulting in the loss of some raw materials, and there are impurity peaks in the XRD analysis spectrum of its product relative to the standard spectrum of ZIF-8 crystals.

[0006] Therefore, there is an urgent need to design a metal-organic framework synthesis method with simple process, low cost, rapid reaction, high product yield and high space-time yield. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a zinc-based metal-organic framework and its preparation method and application. The preparation method provided by the present invention does not require high-temperature and high-pressure equipment, the environmental conditions are mild, the preparation process is simple, safe and controllable, greatly reducing the production difficulty, cost and equipment requirements. And with the assistance of a catalyst, the reaction rate, product yield and space-time yield are greatly improved. This preparation method is green and environmentally friendly, and can prepare a zinc-based metal-organic framework with adjustable structure and properties, having high industrial production prospects and being suitable for application and promotion.

[0008] To achieve the purpose of this invention, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a preparation method of a zinc-based metal-organic framework, and the preparation method includes the following steps:

[0010] Mix a zinc source, a ligand, a catalyst and a solvent, carry out a reaction, and perform post-treatment after the reaction ends to obtain the zinc-based metal-organic framework;

[0011] Wherein, the catalyst includes any one or a combination of at least two of soluble ammonium salts, soluble salts containing metal ions or acids.

[0012] The preparation method provided by the present invention does not require high-temperature and high-pressure equipment, the environmental conditions are mild, the preparation process is simple, safe and controllable, greatly reducing the production difficulty, cost and equipment requirements. And with the assistance of a catalyst, the reaction rate, product yield and space-time yield are greatly improved. This preparation method is green and environmentally friendly, and can prepare a zinc-based metal-organic framework with adjustable structure and properties, having high industrial production prospects and being suitable for application and promotion.

[0013] The catalyst of the present invention is of the above types, with rapid reaction, high yield, low requirements for equipment, and no need for high-temperature and high-pressure reactions in the preparation process, and can quickly synthesize zinc-based metal-organic frameworks.

[0014] The preparation method provided by the present invention can achieve a high product yield, which can reach 95-101% of the theoretical yield, and mostly 98-100%.

[0015] As a preferred technical solution of the present invention, the soluble ammonium salt includes any one or a combination of at least two of ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium oxalate or ammonium acetate.

[0016] Preferably, the soluble salt containing metal ions includes any one or a combination of at least two of nitrates, sulfates, formates, acetates, oxalates or chlorides.

[0017] Preferably, the acid includes any one or a combination of at least two of hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid, phosphoric acid, boric acid, benzoic acid, oxalic acid, terephthalic acid, trimesic acid, fumaric acid, citric acid, ascorbic acid or tannic acid.

[0018] Preferably, before the catalyst is mixed, the catalyst is first formulated into a catalyst solution, and the mass percentage concentration of the catalyst solution is 1-80%, for example, it can be 1%, 10%, 30%, 50%, 70% or 80%, etc., and preferably 5-80%.

[0019] Preferably, the catalyst accounts for 0.1-10% of the total weight of the reactants, for example, it can be 0.1%, 1%, 3%, 5%, 7%, 9% or 10%, etc., preferably 0.2-5%, and more preferably 0.4-4%.

[0020] It should be noted that the total weight of the reactants refers to the total weight of the ligand, catalyst and zinc source.

[0021] In the present invention, if the ratio of the catalyst to the total weight of the reactants is too small, the reaction rate is slow, the space-time yield is reduced, and even the reaction cannot be initiated, and the reactants react incompletely; if the ratio of the catalyst solution to the total weight of the reactants is too large, the local reaction rate is too fast, resulting in difficult dispersion, so that the reactants cannot react homogeneously, and even the reaction is incomplete.

[0022] As a preferred technical solution of the present invention, the zinc source includes any one or a combination of at least two of zinc-containing chlorides, zinc salts, zinc-containing oxides or zinc-containing hydroxides, and preferably zinc-containing oxides and / or zinc-containing hydroxides.

[0023] The above-mentioned zinc source adopted in the present invention is inexpensive and easy to obtain.

[0024] In the present invention, zinc-containing oxides and / or zinc-containing hydroxides are preferred because their reaction products are water and do not cause environmental hazards.

[0025] Preferably, the zinc-containing chloride is zinc chloride.

[0026] Preferably, the zinc salt includes any one or a combination of at least two of zinc carbonate, basic zinc carbonate, zinc nitrate, zinc sulfate, zinc acetate or zinc oxalate, and is preferably zinc carbonate and / or basic zinc carbonate.

[0027] In the present invention, zinc carbonate and / or basic zinc carbonate are preferred because their reaction products are water and carbon dioxide and do not cause environmental hazards.

[0028] Preferably, the zinc-containing oxide is zinc oxide.

[0029] Preferably, the zinc-containing hydroxide is zinc hydroxide.

[0030] Preferably, the ligand includes at least one at least bidentate organic compound.

[0031] Preferably, the at least bidentate organic compound includes any one or a combination of at least two of imidazole, triazole or pyrimidine.

[0032] Preferably, the imidazole includes any one or a combination of at least two of 2-methylimidazole, 2-ethylimidazole or benzimidazole, and is preferably 2-methylimidazole and / or 2-ethylimidazole.

[0033] Preferably, the triazole includes any one or a combination of at least two of 1,2,4-triazole, 3-amino-1,2,4-triazole or 3,5-diamino-1,2,4-triazole, and is preferably 1,2,4-triazole.

[0034] Preferably, the pyrimidine includes 2-hydroxypyrimidine and / or 4-hydroxypyrimidine.

[0035] Preferably, the molar ratio of zinc ions in the zinc source to the ligand is (1-2):(1-4). Among them, the selection range of zinc ions "1-2" can be, for example, 1, 1.2, 1.4, 1.6, 1.8 or 2, etc., and is preferably the stoichiometric ratio of zinc ions in the zinc source to the ligand.

[0036] Preferably, the ligand accounts for 10-90% of the total weight of the reactants, and can be, for example, 10%, 30%, 50%, 70%, 80% or 90%, etc.

[0037] As a preferred technical solution of the present invention, the solvent includes water and / or alcohol, and is preferably water and alcohol.

[0038] Preferably, the alcohol includes any one or a combination of at least two of methanol, ethanol, isopropanol, propanol, ethylene glycol or glycerol.

[0039] Preferably, the volume ratio of the water to the alcohol is (0 - 100):(100 - 0), wherein the selection range of water "0 - 100" can be, for example, 0, 10, 30, 50, 70 or 90, etc., and the selection range of alcohol "0 - 100" can be, for example, , etc., preferably (0 - 70):(30 - 100), more preferably (5 - 50):(50 - 95), and further preferably (10 - 30):(70 - 90).

[0040] As a preferred technical solution of the present invention, the mixing method includes the following steps:

[0041] (a) Mix the ligand and the solvent to obtain a ligand solution;

[0042] (b) Under stirring conditions, co - mix the zinc source, the catalyst and the ligand solution.

[0043] Preferably, the molar concentration of the ligand solution in step (a) is 2 - 15 mol / L, and can be, for example, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L or 10 mol / L, etc.

[0044] Preferably, before the zinc source, the catalyst and the ligand solution are co - mixed in step (b), the zinc source is first formulated into a solution or a suspension.

[0045] Preferably, the co - mixing method in step (b) includes: mixing the zinc source and the ligand solution to obtain a mixed solution, and then adding the catalyst.

[0046] As a preferred technical solution of the present invention, the reaction time is 1 min - 24 h, and can be, for example, 1 min, 0.5 h, 1 h, 6 h, 12 h, 18 h or 24 h, etc., preferably 2 min - 1 h, and more preferably 3 - 30 min.

[0047] In the present invention, in order to obtain a uniformly reacting product and excellent space - time efficiency, the preferred reaction time is 2 min - 1 h.

[0048] Preferably, the reaction temperature is room temperature.

[0049] It should be noted that the present invention does not limit the specific value of room temperature. Exemplarily, for example, it can be 25 ± 5 °C, such as 20 °C, 25 °C or 30 °C, etc.

[0050] Preferably, the post-treatment method includes any one or a combination of at least two of washing, drying or crushing.

[0051] In the present invention, through drying and crushing, zinc-based metal-organic framework powder with complete crystal form can be obtained, and it is allowed to be directly further processed, such as composite film formation or molding.

[0052] In the present invention, the solvent used can be removed by drying.

[0053] Preferably, the drying method includes any one or a combination of at least two of room temperature drying, heating evaporation, vacuum drying, freeze drying, spray drying or continuous tunnel kiln drying.

[0054] Preferably, the temperature of the heating evaporation is 30 - 200 °C, for example, it can be 30 °C, 50 °C, 70 °C, 100 °C, 130 °C, 150 °C, 170 °C or 200 °C, etc., and preferably 80 - 150 °C.

[0055] Preferably, the washing includes water washing or alcohol washing.

[0056] In the present invention, if a metal-organic framework with higher purity is desired, the obtained zinc-based metal-organic framework powder can be washed with alcohol or water to remove a small amount of residual unreacted substances and catalysts in the powder, and then used for other purposes according to the usage environment.

[0057] As a preferred technical solution of the present invention, during the mixing process, an ion dopant is also added.

[0058] The preparation method provided by the present invention can perform multi-ion doping during the reaction to achieve doping modification.

[0059] Preferably, the ion dopant is a metal ion dopant, and the metal ions in the metal ion dopant include Cu 2+ 、Cu + 、Mg 2+ 、Co 3+ 、Co 2+ 、Ca 2+ 、Mn 2+ 、Al 3+ 、Fe 3+ 、Fe 2+ 、Sr 2+ 、Ba 2+ 、Sc 3+ 、Y 3+ 、Ln 3+ 、Ti 4+ 、Zr 4+ 、Hf 4+ 、V 4+ 、V3+ 、V 2+ 、Nb 3+ 、Ta 3+ Cr 3+ 、Mo 3+ 、W 3+ 、Re 3+ 、Re 2+ 、Ru 3+ 、Ru 2+ 、Os 3+ 、Os 2+ , Rh 2+ , Rh + 、Ir 2+ 、Ir + 、Ni 2+ 、Pd 2+ 、Pd + , Pt 2+ , Pt + 、Ag + 、Au + 、Cd 2+ 、Hg 2+ 、Ga 3+ 、In 3+ 、Tl 3+ 、Ge 4+ 、Ge 2+ 、Sn 4+ 、Sn 2+ , Pb 4+ , Pb 2+ 、As 5+ 、As 3+ 、As + 、Sb 5+ 、Sb 3+ 、Sb + 、Bi 5+ 、Bi 3+ Or Bi + Any one or a combination of at least two of the following, preferably Cu 2+ 、Mn 2+ 、Fe 3+ 、Co 3+ 、Ni 2+ 、Al 3+ Mg 2+ 、Ti 4+ 、Zr 4+ 、Y 3+ Sc 3+ 、V 3+ 、In 3+ , Ca 2+ Cr 3+ 、Mo 3+ 、W 3+ or Ln 3+Any one or a combination of at least two of them.

[0060] Preferably, a water repellent is added during the mixing process.

[0061] In the present invention, if it is necessary to improve the water resistance of the zinc-based metal-organic framework material, functional modification can be carried out through a water repellent while the reaction is taking place.

[0062] Preferably, the water repellent includes a hydrophobic silane.

[0063] Preferably, the hydrophobic silane includes dichlorodimethoxysilane and / or octyltrimethoxysilane.

[0064] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0065] (1) At room temperature, the ligand and the solvent are stirred and mixed to obtain a ligand solution with a molar concentration of 2 - 15 mol / L;

[0066] The catalyst and water are mixed to obtain a catalyst solution with a mass percentage concentration of 1 - 80%;

[0067] (2) At room temperature, the zinc source and the ligand solution are stirred and mixed, then the catalyst solution is added, and the reaction is carried out for 1 min - 24 h to obtain a solid product. Then, the solid product is heated and evaporated at 30 - 200 °C for 10 - 20 h, and after pulverization, the powder of the zinc-based metal-organic framework is obtained.

[0068] It should be noted that since the reaction in the preparation method provided by the present invention is rapid and complete, and the solvent ratio and reaction time are adjustable, it can be used as a treatment method for growing zinc-based metal-organic frameworks in other systems. For example, Zn 2+ ions are pre-added to the membrane material, and the prepared ligand solution is used to treat the membrane material, so that the zinc-based metal-organic framework grows in-situ in the membrane material to achieve the use purpose and performance.

[0069] In the second aspect, the present invention provides a zinc-based metal-organic framework prepared by the preparation method as described in the first aspect, and the space-time yield of the zinc-based metal-organic framework is at least 10000 kg / m 3 / d, for example, it can be 10000 kg / m 3 / d, 50000 kg / m 3 / d, 100000 kg / m 3 / d, 300000 kg / m 3 / d or 500000 kg / m 3 / d, etc.

[0070] Preferably, the space-time yield of the zinc-based metal-organic framework is at least 25000 kg / m 3 / d, preferably 50000kg / m 3 / d, more preferably at least 100000-650000 kg / m 3 / d.

[0071] The present invention can achieve ultra-high space-time yield, which is not mentioned in various currently known MOFs synthesis methods.

[0072] It should be noted that the unit "kg / m 3 / d” kg is the amount of product, m 3 is the unit volume, and d is the unit reaction time.

[0073] The zinc-based metal-organic framework particles prepared by the present invention have good MOF structural characteristic peaks, which can be characterized by XRD. For example, zinc-based 2-methylimidazole has a very good ZIF-8 crystal form, with a crystal particle size in the range of 50-500nm and a particle size in the range of 50nm-100μm. Large particles can be further crushed to meet the needs; no ZnO characteristic peak is detected in the zinc-based 2-methylimidazole organic framework, indicating that the reaction in the preparation method provided by the present invention is relatively complete, and Zn 2+ The conversion to MOF was almost complete, which was indirectly confirmed by thermogravimetric analysis and zinc content.

[0074] In a third aspect, the present invention provides an application of the zinc-based metal-organic framework as described in the second aspect in the fields of adsorption, separation, catalysis, energy storage, sensors, drug transport and carbon fixation.

[0075] The numerical range described in the present invention includes not only the point values listed above, but also any point values between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] (1) The preparation method provided by the present invention does not require high-temperature and high-pressure equipment, operates under mild environmental conditions, and has a simple, safe, and controllable preparation process, significantly reducing production difficulty, cost, and equipment requirements. Furthermore, with the assistance of a catalyst, it significantly improves reaction rate, product yield, and space-time yield. This preparation method is environmentally friendly and can produce a zinc-based metal-organic framework with adjustable structure and properties. It has high industrial production prospects and is suitable for application and promotion.

[0078] (2) In the process of preparing the zinc-based metal-organic framework of the present invention, product modification and multi-metal doping can be carried out simultaneously to achieve the purpose of use and functionalization. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 It is a process flow diagram for preparing the zinc-based metal-organic framework in Example 1 of the present invention.

[0080] Figure 2 It is an XRD pattern of the zinc-based metal-organic framework prepared in Example 1 of the present invention.

[0081] Figure 3 It is a nitrogen adsorption-desorption curve of the zinc-based metal-organic framework prepared in Example 1 of the present invention.

[0082] Figure 4 It is an XRD pattern of the zinc-based metal-organic framework prepared in Example 2 of the present invention.

[0083] Figure 5 It is an XRD pattern of the zinc-based metal-organic framework prepared in Example 3 of the present invention.

[0084] Figure 6 It is an XRD pattern of the zinc-based metal-organic framework prepared in Example 4 of the present invention.

[0085] Figure 7 It is an XRD pattern of the zinc-based metal-organic framework prepared in Example 5 of the present invention.

[0086] Figure 8 It is an XRD pattern of the zinc-based metal-organic framework prepared in Example 8 of the present invention.

[0087] Figure 9 It is an XRD pattern of the zinc-based metal-organic framework prepared in Example 9 of the present invention.

[0088] Figure 10 It is an XRD pattern of the zinc-based metal-organic framework prepared in Example 10 of the present invention.

[0089] Figure 11 It is an XRD pattern of the zinc-based metal-organic framework prepared in Example 11 of the present invention.

[0090] Figure 12 It is an XRD pattern of the zinc-based metal-organic framework prepared in Example 12 of the present invention.

[0091] Figure 13 It is an XRD pattern of the zinc-based metal-organic framework prepared in Example 13 of the present invention.

[0092] Figure 14This is the XRD pattern of the zinc-based metal-organic framework prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0093] In order to further illustrate the present invention and its advantages, the technical scheme of the present invention is further described below by specific embodiments. It should be understood that these embodiments only help to understand the present invention and should not be regarded as specific limitations of the present invention. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention related to in the following description are only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention. The raw materials and reagents used in the present invention are all commercially available industrial products. The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments of the specification.

[0094] The raw materials used in the present invention are all commercially available products and are not further purified during the synthesis process.

[0095] It should be noted that the room temperature below refers to 25°C.

[0096] Example 1

[0097] This embodiment provides a method for preparing a zinc-based metal-organic framework, and its process flow chart is as follows: Figure 1 As shown, the preparation method comprises the following steps:

[0098] (1) At room temperature, 32.84 g of ligand and 45 mL of solvent were stirred to obtain a ligand solution with a molar concentration of 8.9 mol / L;

[0099] 2 g of the catalyst was added to 5 mL of deionized water and dissolved to obtain a catalyst solution with a mass percent concentration of 28.6%;

[0100] Wherein, the ligand is 2-methylimidazole, the amount of which is 0.4 mol, the solvent is methanol, and the catalyst is ammonium sulfate;

[0101] (2) at room temperature, 16.28 g of the zinc source and the ligand solution were stirred and mixed, and then the catalyst solution was added and reacted for 10 min to obtain a solid product, and then the solid product was heated and evaporated at 80° C. for 16 h, and crushed to obtain the zinc-based metal-organic framework powder;

[0102] Among them, the zinc source is zinc oxide with a molar amount of 0.2 mol, the solid product is zinc-based 2-methylimidazole, the catalyst accounts for 3.91% of the total weight of the reactants (i.e., the ligand, the catalyst and the zinc source), the molar ratio of zinc ions in the zinc source to the ligand is 2:4, and the ligand accounts for 64.24% of the total weight of the reactants.

[0103] Figure 2 The XRD pattern of the zinc-based metal-organic framework prepared in this example is shown. As can be seen from the figure, no ZnO characteristic peak is detected in the zinc-based metal-organic framework, indicating that the reaction in the preparation method provided by the present invention proceeds relatively completely, and Zn 2+ is almost completely converted into MOF.

[0104] Figure 3 The nitrogen adsorption-desorption isotherm curve of the zinc-based metal-organic framework obtained in this example is shown. As can be seen from the figure, the synthesized zinc-based metal-organic framework compound has a rich microporous structure and a very high specific surface area. The BET specific surface area is 1576.11 m 2 / g, and the Langmuir specific surface area is 1694.58 m 2 / g.

[0105] Example 2

[0106] This example provides a preparation method of a zinc-based metal-organic framework. The preparation method includes the following steps:

[0107] (1) Under room temperature conditions, 41.05 g of the ligand and 50 mL of the solvent are stirred and mixed to obtain a ligand solution with a molar concentration of 10 mol / L;

[0108] 1.25 g of the catalyst is added to 4 mL of deionized water and dissolved to obtain a catalyst solution with a mass percentage concentration of 23.8%;

[0109] Among them, the ligand is 2-methylimidazole with a molar amount of 0.5 mol, the solvent includes 25 mL of methanol and 25 mL of water, and the catalyst is ammonium nitrate;

[0110] (2) Under room temperature conditions, 20.35 g of the zinc source and the ligand solution are stirred and mixed, then the catalyst solution is added, and a reaction is carried out for 5 min to obtain a solid product. Then, the solid product is heated and evaporated at 120 °C for 16 h, and after being crushed, the powder of the zinc-based metal-organic framework is obtained;

[0111] Among them, the zinc source is zinc oxide with a molar amount of 0.25 mol. The solid product is zinc-based 2-methylimidazole. The catalyst accounts for 2% of the total weight of the reactants (i.e., the ligand, the catalyst, and the zinc source). The molar ratio of zinc ions in the zinc source to the ligand is 1:2, and the ligand accounts for 65.52% of the total weight of the reactants.

[0112] Figure 4 The XRD pattern of the zinc-based metal-organic framework obtained in this example is shown. As can be seen from the figure, no ZnO characteristic peak is detected in the zinc-based metal-organic framework, indicating that the reaction in the preparation method provided by the present invention proceeds relatively completely.

[0113] Example 3

[0114] This example provides a preparation method of a zinc-based metal-organic framework. The preparation method includes the following steps:

[0115] (1) At room temperature, 32.84 g of the ligand and 60 mL of the solvent are stirred and mixed to obtain a ligand solution with a molar concentration of 6.7 mol / L.

[0116] 0.63 g of the catalyst is added to the ligand solution and dissolved to obtain a mixed solution.

[0117] Among them, the ligand is 2-methylimidazole with a molar amount of 0.4 mol. The solvent includes 50 mL of methanol and 10 mL of water. The catalyst is oxalic acid.

[0118] (2) At room temperature, 16.28 g of the zinc source and the ligand solution are stirred and mixed, and a reaction is carried out for 30 min to obtain a solid product. Then, the solid product is heated and evaporated at 120 °C for 16 h, and after being crushed, the powder of the zinc-based metal-organic framework is obtained.

[0119] Among them, the zinc source is zinc oxide with a molar amount of 0.2 mol. The solid product is zinc-based 2-methylimidazole. The molar ratio of zinc ions in the zinc source to the ligand is 1:2, and the ligand accounts for 66.01% of the total weight of the reactants.

[0120] Figure 5 The XRD pattern of the zinc-based metal-organic framework obtained in this example is shown. As can be seen from the figure, no ZnO characteristic peak is detected in the zinc-based metal-organic framework, indicating that the reaction in the preparation method provided by the present invention proceeds relatively completely.

[0121] Example 4

[0122] This example provides a preparation method of a zinc-based metal-organic framework. The preparation method includes the following steps:

[0123] (1) At room temperature, 32.84 g of ligand and 50 mL of solvent were stirred to obtain a ligand solution with a molar concentration of 8 mol / L;

[0124] 2 g of catalyst was added to 2 mL of deionized water to dissolve to obtain a catalyst solution with a mass percent concentration of 50%;

[0125] The ligand is 2-methylimidazole, the amount of which is 0.4 mol, the solvent includes 45 mL of methanol and 5 mL of water, and the catalyst is ammonium nitrate;

[0126] (2) at room temperature, 16.28 g of the zinc source and the ligand solution were stirred and mixed, and then the catalyst solution was added and reacted for 2 min to obtain a solid product, and then the solid product was heated and evaporated at 120° C. for 16 h, and crushed to obtain the zinc-based metal-organic framework powder;

[0127] The zinc source is zinc oxide, the amount of which is 0.2 mol, the solid product is zinc-2-methylimidazole, the catalyst accounts for 3.91% of the total weight of the reactants (i.e., the ligand, the catalyst and the zinc source), the molar ratio of zinc ions and ligands in the zinc source is 1:2, and the ligand accounts for 64.24% of the total weight of the reactants.

[0128] Figure 6 The XRD pattern of the zinc-based metal-organic framework obtained in this example is shown. As can be seen from the figure, no ZnO characteristic peak is detected in the zinc-based metal-organic framework, indicating that the reaction in the preparation method provided by the present invention is relatively complete.

[0129] Example 5

[0130] This embodiment provides a method for preparing a zinc-based metal-organic framework, the preparation method comprising the following steps:

[0131] (1) At room temperature, 32.84 g of ligand and 45 mL of solvent were stirred to obtain a ligand solution with a molar concentration of 8.9 mol / L;

[0132] Prepare 1 mol / L hydrochloric acid solution as catalyst solution;

[0133] Wherein, the ligand is 2-methylimidazole, the amount of which is 0.4 mol, the solvent is methanol, and the catalyst solution is hydrochloric acid solution;

[0134] (2) At room temperature, 16.28 g of zinc source and the ligand solution were stirred and mixed, then 5 mL of the catalyst solution was added, and the reaction was carried out for 30 min to obtain a solid product. Then, the solid product was heated and evaporated at 120 °C for 16 h, and after being crushed, the powder of the zinc-based metal-organic framework was obtained;

[0135] Among them, the zinc source was zinc oxide, with a molar amount of 0.2 mol. The solid product was zinc-based 2-methylimidazole. The catalyst accounted for 0.4% of the total weight of the reactants (i.e., ligand, catalyst, and zinc source). The molar ratio of zinc ions in the zinc source to the ligand was 1:2, and the ligand accounted for 66.5% of the total weight of the reactants.

[0136] Figure 7 The XRD pattern of the zinc-based metal-organic framework obtained in this example is shown. It can be seen from the figure that no ZnO characteristic peak was detected in the zinc-based metal-organic framework, indicating that the reaction in the preparation method provided by the present invention proceeded relatively completely.

[0137] Example 6

[0138] This example provides a preparation method of a zinc-based metal-organic framework. The preparation method includes the following steps:

[0139] (1) At room temperature, 32.84 g of ligand and 45 mL of solvent were stirred and mixed to obtain a ligand solution with a molar concentration of 8 mol / L;

[0140] 1 g of catalyst was added to 2.5 mL of deionized water and dissolved to obtain a catalyst solution with a mass percentage concentration of 28.6%;

[0141] Among them, the ligand was 2-methylimidazole, with a molar amount of 0.4 mol. The solvent was methanol, and the catalyst was ammonium sulfate;

[0142] (2) At room temperature, 16.28 g of zinc source and the ligand solution were stirred and mixed, then the catalyst solution was added, and the reaction was carried out for 50 min to obtain a solid product. Then, the solid product was heated and evaporated at 120 °C for 16 h, and after being crushed, the powder of the zinc-based metal-organic framework was obtained;

[0143] Among them, the zinc source was zinc oxide, with a molar amount of 0.2 mol. The solid product was zinc-based 2-methylimidazole. The catalyst accounted for 2.0% of the total weight of the reactants (i.e., ligand, catalyst, and zinc source). The molar ratio of zinc ions in the zinc source to the ligand was 1:2, and the ligand accounted for 65.52% of the total weight of the reactants.

[0144] Example 7

[0145] This embodiment provides a method for preparing a zinc-based metal-organic framework, and the preparation method includes the following steps:

[0146] (1) Under room temperature conditions, 1642 g of a ligand and 2300 mL of a solvent are stirred and mixed to obtain a ligand solution with a molar concentration of 8.7 mol / L;

[0147] 50 g of a catalyst is added to 500 mL of deionized water and dissolved to obtain a catalyst solution with a mass percentage concentration of 9.09%;

[0148] Among them, the ligand is 2-methylimidazole, with a molar amount of 20 mol, the solvent is methanol, and the catalyst is ammonium sulfate;

[0149] (2) Under room temperature conditions, 813.9 g of a zinc source and the ligand solution are stirred and mixed, then the catalyst solution is added, and a reaction is carried out for 5 min to obtain a solid product. Then, the solid product is heated and evaporated at 120 °C for 16 h, and after being crushed, the powder of the zinc-based metal-organic framework is obtained;

[0150] Among them, the zinc source is zinc oxide, with a molar amount of 10 mol, the solid product is zinc-based 2-methylimidazole, the catalyst accounts for 2.0% of the total weight of the reactants (i.e., the ligand, the catalyst, and the zinc source), and the molar ratio of zinc ions in the zinc source to the ligand is 1:2, and the ligand accounts for 65.5% of the total weight of the reactants.

[0151] Example 8

[0152] The difference between this embodiment and Example 1 is that the catalyst accounts for 0.05% of the total weight of the reactants.

[0153] The remaining preparation methods and parameters are the same as those in Example 1.

[0154] Figure 8 The XRD pattern of the zinc-based metal-organic framework obtained in this embodiment is shown. It can be seen from the figure that there are ZnO characteristic peaks, indicating that in the preparation method provided in this embodiment, the reaction of the reactants is not complete.

[0155] Example 9

[0156] The difference between this embodiment and Example 1 is that the catalyst accounts for 15% of the total weight of the reactants.

[0157] The remaining preparation methods and parameters are the same as those in Example 1.

[0158] Figure 9The XRD pattern of the zinc-based metal-organic framework obtained in this example is shown. As can be seen from the figure, there are characteristic peaks of ZnO and other impurity peaks that are not synthesized MOF, indicating that the preparation method provided in this example has uneven reaction during the synthesis process and is difficult to control.

[0159] Example 10

[0160] The difference between this embodiment and embodiment 1 is that the reaction time in step (2) is 30 s.

[0161] The rest of the preparation methods and parameters remained the same as in Example 1.

[0162] Figure 10 The XRD pattern of the zinc-based metal-organic framework obtained in this example is shown. As can be seen from the figure, there is a characteristic peak of ZnO, which shows that the reaction of the reactants in the preparation method provided in this example is not complete.

[0163] Example 11

[0164] The difference between this embodiment and embodiment 1 is that the reaction time in step (2) is 30 h.

[0165] The rest of the preparation methods and parameters remained the same as in Example 1.

[0166] Figure 11 The XRD pattern of the zinc-based metal-organic framework obtained in this embodiment is shown. It can be seen from the figure that it is almost consistent with that in Example 1. No ZnO characteristic peak is detected in the zinc-based metal-organic framework, indicating that the reaction in the preparation method provided by the present invention is relatively complete. 2+ Almost completely converted into MOF. No need to extend the reaction time, resulting in energy waste and reduced space-time yield. Example 12

[0167] The difference between this embodiment and embodiment 1 is that during the reaction of step (2), a Cu-containing 2+ Metal ion dopant, added amount: molar ratio Cu 2+ :Zn 2+ =2:98.

[0168] The rest of the preparation methods and parameters remained the same as in Example 1.

[0169] Figure 12 The XRD pattern of the zinc-based metal-organic framework obtained in this example is shown. As can be seen from the figure, there is no ZnO characteristic peak, indicating that the reaction in the preparation method provided by the present invention is relatively complete. Example 13

[0170] The difference between this embodiment and embodiment 1 is that a hydrophobic agent, dichlorodimethoxysilane, is further added during the reaction of step (2), and the added amount is 2% of the total weight of the reactants.

[0171] The rest of the preparation methods and parameters remained the same as in Example 1.

[0172] Figure 13 The XRD pattern of the zinc-based metal-organic framework obtained in this example is shown. As can be seen from the figure, there is no ZnO characteristic peak, indicating that the reaction in the preparation method provided by the present invention is relatively complete.

[0173] The difference between this comparative example and Example 1 is that the catalyst solution is not prepared in step (1), so that the catalyst solution is not added in step (2).

[0174] The rest of the preparation methods and parameters were the same as those in Example 1.

[0175] Figure 14 The XRD pattern of the zinc-based metal-organic framework obtained in this comparative example is shown. It can be seen from the figure that the zinc-based metal-organic framework has a strong ZnO characteristic peak and a weak zinc-based MOF peak, indicating that the preparation method provided in this example has a very low reaction ratio of the reactants.

[0176] Performance Testing

[0177] The reaction rate, product yield and space-time yield in the preparation methods provided in the above examples and comparative examples were detected. The specific calculation method is:

[0178] The reaction rate is measured by the reaction time, and the product yield is calculated by the ratio of the mass of the obtained zinc-based metal-organic framework powder to the mass calculated based on the molar amount of zinc source added. The yield calculation formula is:

[0179]

[0180] The space-time yield calculation formula is:

[0181]

[0182] The test results are shown in Table 1.

[0183] Table 1

[0184]

[0185] analyze:

[0186] As shown in the table above, the preparation method provided by the present invention features mild environmental conditions, rapid reaction, high product yield, and ultra-high space-time yield. Furthermore, product modification and multi-metal doping can be performed simultaneously during the synthesis process to achieve functionalization. Furthermore, this synthesis invention requires minimal equipment and therefore has great potential for industrial production and is suitable for widespread application.

[0187] It can be seen from Example 1 and Examples 8-9 that if the amount of catalyst added is too little, the reaction time will be prolonged, and it may also cause incomplete reaction and reduced yield; if the amount of catalyst added is too much, the reaction will be too fast locally, resulting in uneven reaction, which still prevents the reaction from being fully carried out in a homogeneous phase and reduces the yield.

[0188] It can be seen from Examples 1 and 10-11 that if the reaction time is too short, some zinc source will not be completely reacted, and the yield will be reduced; if the reaction time is too long, since the reaction is already completed, unnecessary time is added, resulting in energy waste and reduced space-time yield.

[0189] From Example 1 and Example 12-13, it can be seen that if Cu is added during the reaction 2+ The metal ion dopant can be evenly doped into the zinc-based MOF without significantly affecting the structure of the final product. If the hydrophobic agent dichlorodimethoxysilane is also added during the reaction, the hydrophobic properties of the product can be improved. The hydrophobically modified powder can improve its stability and gas adsorption capacity in a high humidity environment, and is expected to be used in a variety of specific environments, with important potential application value.

[0190] It can be seen from Example 1 and Comparative Example 1 that if no catalyst solution is added, then in the absence of a catalyst, according to the stoichiometric ratio of metal to ligand, the reaction ratio of the reactants is very low and the reaction cannot be completed in a short time.

[0191] The applicant states that while the above-described embodiments illustrate the process of the present invention, the present invention is not limited to the above-described process steps, nor does it imply that the present invention must rely on the above-described process steps for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A preparation method of a zinc-based metal-organic framework, characterized in that, The preparation method includes the following steps: Mix a zinc source, a ligand, a catalyst, and a solvent, carry out a reaction, and perform post-treatment after the reaction ends to obtain the zinc-based metal-organic framework; Wherein, the catalyst includes any one or a combination of at least two of a soluble ammonium salt, a soluble salt containing a metal ion, or an acid.

2. The preparation method according to claim 1, characterized in that, The soluble ammonium salt includes any one or a combination of at least two of ammonium carbonate, ammonium bicarbonate, ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium oxalate, or ammonium acetate; Preferably, the soluble salt containing a metal ion includes any one or a combination of at least two of nitrates, sulfates, formates, acetates, oxalates, or chlorides; Preferably, the acid includes any one or a combination of at least two of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, formic acid, acetic acid, benzoic acid, oxalic acid, terephthalic acid, trimesic acid, fumaric acid, citric acid, ascorbic acid, or tannic acid; Preferably, before the catalyst is mixed, the catalyst is first formulated into a catalyst solution, and the mass percentage concentration of the catalyst solution is 1-80%, preferably 5-80%; Preferably, the catalyst accounts for 0.1-10% of the total weight of the reactants, preferably 0.2-5%, and more preferably 0.4-4%.

3. The preparation method according to claim 1 or 2, characterized in that, The zinc source includes any one or a combination of at least two of zinc-containing chlorides, zinc salts, zinc-containing oxides, or zinc-containing hydroxides, preferably zinc-containing oxides and / or zinc-containing hydroxides; Preferably, the zinc-containing chloride is zinc chloride; Preferably, the zinc salt includes any one or a combination of at least two of zinc carbonate, basic zinc carbonate, zinc nitrate, zinc sulfate, zinc acetate, or zinc oxalate, preferably zinc carbonate and / or basic zinc carbonate; Preferably, the zinc-containing oxide is zinc oxide; Preferably, the zinc-containing hydroxide is zinc hydroxide; Preferably, the ligand includes at least one at least bidentate organic compound; Preferably, the at least bidentate organic compound includes any one or a combination of at least two of imidazole, triazole, or pyrimidine; Preferably, the imidazole includes any one or a combination of at least two of 2-methylimidazole, 2-ethylimidazole, or benzimidazole, preferably 2-methylimidazole and / or 2-ethylimidazole; Preferably, the triazole includes any one or a combination of at least two of 1,2,4-triazole, 3-amino-1,2,4-triazole, or 3,5-diamino-1,2,4-triazole, preferably 1,2,4-triazole; Preferably, the pyrimidine includes 2-hydroxypyrimidine and / or 4-hydroxypyrimidine; Preferably, the molar ratio of zinc ions in the zinc source to the ligand is (1-2):(1-4), preferably the stoichiometric ratio of zinc ions in the zinc source to the ligand; Preferably, the ligand accounts for 10-80% of the total weight of the reactants.

4. The preparation method according to any one of claims 1 to 3, characterized in that The solvent includes water and / or alcohol; Preferably, the alcohol includes any one or a combination of at least two of methanol, ethanol, isopropanol, propanol, ethylene glycol, or glycerol; Preferably, the volume ratio of water to alcohol is (0 - 100):(100 - 0), preferably (0 - 70):(30 - 100), more preferably (5 - 50):(50 - 95), and even more preferably (10 - 30):(70 - 90).

5. The preparation method according to any one of claims 1-4, characterized in that, The mixing method includes the following steps: (a) Mix the ligand and the solvent to obtain a ligand solution; (b) Under stirring conditions, co - mix the zinc source, the catalyst and the ligand solution; Preferably, the molar concentration of the ligand solution in step (a) is 2 - 15 mol / L; Preferably, before co - mixing the zinc source, the catalyst and the ligand solution in step (b), the zinc source is first formulated into a solution or a suspension; Preferably, the co - mixing method in step (b) includes: mixing the zinc source and the ligand solution to obtain a mixed solution, and then adding the catalyst.

6. The preparation method according to any one of claims 1-5, characterized in that, The reaction time is 1 min - 24 h, preferably 2 min - 1 h, and more preferably 3 - 30 min; Preferably, the reaction temperature is room temperature; Preferably, the post - treatment method includes any one or a combination of at least two of washing, drying or crushing; Preferably, the drying method includes any one or a combination of at least two of room - temperature drying, heating evaporation, vacuum drying, freeze - drying, spray drying or continuous tunnel kiln drying; Preferably, the temperature of the heating evaporation is 30 - 200 °C, preferably 80 - 150 °C.

7. The preparation method according to any one of claims 1-6, characterized in that, During the mixing process, an ion dopant is also added; Preferably, the ion dopant is a metal ion dopant, and the metal ions in the metal ion dopant include Cu 2+ 、Cu + Mg 2+ 、Co 3+ 、Co 2+ , Ca 2+ 、Mn 2+ 、Al 3+ 、Fe 3+ 、Fe 2+ 、Sr 2+ 、Ba 2+ Sc 3+ 、Y 3+ 、Ln 3+ 、Ti 4+ 、Zr 4+ , Hf 4+ 、V 4+ 、V 3+ 、V 2+ 、Nb 3+ 、Ta 3+ Cr 3+ 、Mo 3+ 、W 3+ 、Re 3+ 、Re 2+ 、Ru 3+ 、Ru 2+ 、Os 3+ 、Os 2+ , Rh 2+ , Rh + 、Ir 2+ 、Ir + 、Ni 2+ 、Pd 2+ 、Pd + , Pt 2+ , Pt + 、Ag + 、Au + 、Cd 2+ 、Hg 2+ 、Ga 3+ 、In 3+ 、Tl 3+ 、Ge 4+ 、Ge 2+ 、Sn 4+ 、Sn 2+ , Pb 4+ , Pb 2+ 、As 5+ 、As 3+ 、As + 、Sb 5+ 、Sb 3+ 、Sb + 、Bi 5+ , Bi 3+ or Bi + or any combination of at least two of them, preferably Cu 2+ , Mn 2+ , Fe 3+ , Co 3+ , Ni 2+ , Al 3+ , Mg 2+ , Ti 4+ , Zr 4+ , Y 3+ , Sc 3+ , V 3+ , In 3+ , Ca 2+ , Cr 3+ , Mo 3+ , W 3+ or Ln 3+ or any combination of at least two of them; Preferably, during the mixing process, a hydrophobic agent is also added; Preferably, the hydrophobic agent includes hydrophobic silane; Preferably, the hydrophobic silane includes dichlorodimethoxysilane and / or octyltrimethoxysilane.

8. The preparation method according to any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: (1) Under room - temperature conditions, stir and mix the ligand and the solvent to obtain a ligand solution with a molar concentration of 2 - 15 mol / L; Mix the catalyst and water to obtain a catalyst solution with a mass percentage concentration of 1 - 80%; (2) Under room - temperature conditions, stir and mix the zinc source and the ligand solution, then add the catalyst solution, carry out a reaction for 1 min - 24 h to obtain a solid product, and then carry out heating evaporation on the solid product at 30 - 200 °C for 10 - 20 h, and pulverize to obtain the powder of the zinc - based metal - organic framework.

9. A zinc-based metal-organic framework prepared by the preparation method according to any one of claims 1-8, characterized in that, The space-time yield of the zinc-based metal-organic framework is at least 10,000 kg / m 3 / d; Preferably, the space-time yield of the zinc-based metal-organic framework is at least 25000 kg / m 3 / d, preferably 50000 kg / m 3 / d, more preferably at least 100000 - 650000 kg / m 3 / d.

10. Use of a zinc - based metal - organic framework as claimed in claim 9 in the fields of adsorption, separation, catalysis, energy storage, sensors, drug delivery and carbon sequestration.

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